The goal of the proposed institutional-based Physician-Scientist Training Program is to provide broad and intensive training of young physicians in biomedical science to equip them for successful careers as independent and original scientists in academic medicine. The new program provides the stimulus to an intensive training program that arises naturally out of the prior research and research training experience and tradition of the Massachusetts General Hospital, the nature of the housestaff and other physicians who come to the MGH for training, and the strong ties that exist in basic science between the faculty at MGH and their colleagues in the basis science departments at Harvard and MIT. It is essential to give physicians broad training in basic concepts of biomedical science over an extended period of time, coupled with extensive research experience in outstanding laboratories, if they are to develop as outstanding scientists themselves, a most important goal given the remarkable impact of the revolution in biology on the practice of medicine. Candidates for the training program will be selected from the many outstanding House Officers that come to the Department of Medicine and other Departments within the MGH and those that apply from other institutions. A Program Steering Committee, composed of physician-scientists at the MGH in the four major program areas of the NIADDK Program and experienced basic scientists particularly dedicated to the education of M.D.s and Ph.D.s in careers of science, will work with the Program Director to guarantee the selection of the most deserving candidates, carefully plan the individual didactic program of each physician-scientist supported, and thoroughly review the progress of research with the Sponsor in the basic science laboratory. Candidates will be permitted to advance from Phase I after two, or often three years, into Phase II only after rigorous review by the Program Steering Committee provides satisfactory evidence of their growth in scientific experience and basic biological knowledge. Successful graduates of the Physician-Scientist Training Program will be assured of faculty positions at MGH and the Harvard Medical School. A pre-doctoral training program will be requested, as well, to permit students from Harvard Medical School or the Harvard/MIT joint program to interrupt their medical school training in order to take one or two years of intensive research.